Preloaded air release chuck



Oct. 13, 1953 E PETERSON 2,655,384

PRELOADED AIR RELEASE CHUCK Filed July 28, 1947 T Ta QPWWM E. L. PETERSON Patented Oct. 13, 1953 UNITED STATES rATENT OFFICE 3 r 2,655,384 'PRELOADED AIR RELEASE CHUCK Elwin L. Peterson, Falls Church, Va. Application July 28, 1947, Serial No. 764,103

This invention relates to apparatus for hold- "ing standard collets and the like. More particularly this invention relates to a preloaded air release chuck for use in holding collets in lathes, drill presses and the like.

An object of this invention is to provide a collet chuck for drill presses, lathes and the like in which the work is held by a constant pressure from which it is released by a counteracting air pressure.

Another object of this invention is to provide a Work holding chuck for drill presses, lathes and the like that can be opened while in motion.

Still another object of this invention is to provide a chuck of simple construction that will hold work pieces of all sizes with the same pressure.

A further object of this invention is to provide a chuck for use with collets in which no drawbar is necessary.

Other and further objects of this invention will be apparent to those skilled in the art to which this invention relates from the following specification, claims and drawing.

Heretofore air chucks manufactured by various concerns required that air be piped to the revolving spindleand to the chuck and as a result small high speed lathes were seldom if ever equipped with such chucks. In these prior art chucks continuous air pressure wasyrequired to hold the work and if the air pressure failed the work wasreleased by the chuck, permitting to fly out of the chuck. t

A feature of the present invention is the provision of a preloaded chuck in which the force n of this preloading gripsthe collet holdingthe work until the preloading is counteracted by air pressure that may be applied by the operator.

The chuck is provided with a threaded portion for receiving corresponding threads of; the collet and this obviates the necessity for using a drawbar. Furthermore, this also prevents the collet from moving laterally when closed and in addition a screw threaded stop may be inserted behind the collet to be used as an adjustable stop m work. Other features of this invention will be set forth inthe specification, claims and drawing in which briefly a Fig. l is a view in front elevation in fragmentary section of the chuck, and

Fig. 2 is a sectional view along the lines 2-2 of Fig.1. t l

Referring to the drawing in detail reference numeral 10 designates the chuck housing having 7 Claims. (01. 279-4 2 a threaded spindle portion ll adapted to be at.- tached to the threaded spindle of a lathe, drill press, milling machine or the like. A suitable threaded hole 12 substantially in the center of the housing is provided for the purpose of receiving the threaded end of the collet l3 having a. slightly tapered hole extending therethrough and having the forward end thereof split in at least three equally spaced places along the circumference so as to be compressible for the purpose of grip.- ping work in said hole. The cavity of the housing IE! is provided with an inflatable elastic liniing i l having a check valve l5 attached thereto for the purpose of permitting inflation of the lining 14 from a suitable source of compressed air. This lining l4 and compressed air are employed for the purpose of applying pressure to the piston l6 so that this piston forces the tapered surface 20 of the cylindrical extension Ill that is integral with the piston it, into engagement with the inclined surface [9 of the collet l3 and thereby compresses the split end of the collet I13 causing it to grip the work. Suitable gaskets I1 and 2| are provided to the piston ['6 and the cylindrical extension I B and these gaskets may be provided with graphite lubrication.

The collet I3 ,is also provided with a notch for receiving the spring urged ball 22 therein to limit movement of the collet when it is released by the clamping member l8.

Releasing the collet I 3 is accomplished by forcing compressed air into the chamber 34 formed between thepiston l6 and the end or cover plate 23 that is bolted over the opening ofthe housing [0. Compressed air is supplied to the pipe 28 through asmall manualvalve 29 and when "this valve 29 is opened by the operator compressed air flows from the mouth or nozzle 28a of the pipe 2 8. against the rubber flap 21 and moves this rubber flap 2! outof, the way thereby permitting compressed air to enter the space between plate 23 and the disc 25 that is mounted by threads 26 on the cylindrical projection integral with "the plate 23.- From this space compressed air enters the cavity 34 through the holes '24 and pressure is applied to the piston 16 compressing the plastic chamber M and thereby moving the tapered surface 2t of the cylindrical extension l3 inward and releasing pressure on the inclined surface I9 of the collet l3 so that the work gripped by the collet is released.

Ordinarily the compressed air forced into the chamber will leak out of this cavity and permit the pressure in the chamber [4 to again force the cylindrical extension l8 to clamp the collet as previously described. However, in order to release this air pressure from the cavity 34 as desired, a plurality of holes 3| normally closed by the rubber ring 30, are provided to the disc 25 and these holes 3! may be opened by pressing the ring 32 toward the plate or disc 25 causing the pins 33 to move the flap 30 away from the holes 3|. Suitable springs are provided around the pins 33 to hold the ring 32 away from the disc and permit the flap 3,0 to maintain the holes 3| closed. The inner ends of the pins 33 are of course provided with heads to prevent the springs from forcing these pins out of the corresponding holes completely. The flexible rings 21 and 30 may be made of natural or synthetic rub-ber, plifilm and the like and they are cemented to the disc 25 by suitable cements so that the circumference 21a and adjacent surface of the ring 21 are cemented to the disc .25 and the circumference 80a and adjacent por- .tions of the ring 3!] are cemented to the .disc 25.

In this way the edge21b of the ring 21 is forced aga nst the adjoining surfaces ofthe plate 23 and. the portions 3% of the ring 30 covering the holes, .31 are normally maintained in closed contact with the inner. edges of these holes. It is of. course obvious that in place of the ring 32, rubbel'nflap .30, pins 33 and holes 3| two or three smallmanually operated check valves may be threaded into suitable holes formed in the plate 25 to be used for the-same purpose of releasing air pressure from the cavity 34. Furthermore, if desired, one .or more valves may be provided in the plate '23 andcompressed air may be fed into the cavity 34 through these valves instead of past therubber flap 21.7 However, in that case the chuck mus be brought to a standstill before air pressure can be supplied to the chamber 34 ans the ork released vfrom the collet. In the constructionillustrated air pressure can be fed to the chamber 34 past the flap 21 and-through. the holes 24 while the chuck is still in motion and the work released from the collet so that a new work piece may be inserted into the collect without bringing the chuck to a standstill.

Furthermore, inv some instances it may be desirable to replace the air bladder M by a plurality-Of suitable coil or leaf springs and in that case. suitable notches may be provided in the walls of the housing 10 and the piston l6 for receiving an h ld ng theends of the sp Ernplo ing Springs in place of the air bladder 1.4 however is not desirable where. different types r, stock are to be ,61 1 in the chuck,-v For exam pleg it may be desired to hold steel ,brass and similar metallic material in the chuck for certain operations andin that casethe pressure in the bladder L4 may, be. Substantial. However, plastic or glass stock may be inserted in the [chuck in order operationsand in this case the pressure in, the lining l4 employed for steel, brass andv he likemight be considerably too high. By using the inflated lining l4 provided with the valve [5 the pressure maybe adjusted for all kinds of stock, a

While ,I have described this. apparatus detail with respect to the preferred embodiment thereof, it is of course apparent that modifications may be made without departing from the scope and spirit of this invention as set forth in the following claims.

I claim:

I. A collet chuck for lathes or the like comprising a substantially circular open ended housing having an annular cavity therein, and having a hole substantially in the center thereof, a collet threaded into said hole, a piston positioned in said annular cavity, said piston having a member for engaging and compressing said collet, means for normally holding said member in engagement with said collet, an aperture plate for substantially closing the open end of said' housing, a disc shaped member supported on said apertured plate in space relation therewith whereby the apertures through said plate open into the space between said plate and said disc shaped member, a flexible seal for said space and. means for forcing compressed air through said seal and said apertures into the space between said plate and said piston for releasing the pressure on said collet.

2. A collet chuck adapted to be mounted on the live spindle of a lathe or the like comprising ,a substantially circular open ended housing having an annular cavity therein and having a hole substantially in the center thereof, a collet threaded into said hole, a piston positioned in said annular cavity said, piston having a member for engaging and compressing said collet, means for normally holdingsaid piston member in engagement with said collet, an .apertured plate for substantially closing the open end-of said housing, a disc shaped member supp rted on said apertured plate in spacedrelation therewith whereby the apertures through said plate open into the space between said plate member and said disc shaped member, a flexible seal for said space engaging said plate and said disc shaped member substantia y alon museumferences thereof and means. for forcingi'compressed air past said seal and through said apertures into the space between said plate and said piston for releasing the pressure on said collet,- i v 3. ma fluid pressure-operated lllsl iqe a rotary head structure defining a pressure chamber and a port through a wall thereof connecting said. pressure .chamber to atmosphere an inwardlyopening check valve closing said port, and a nonrotary nozzle for directing a highly'corrcentrated jet of fluid under pressure toward said head and the path of rotary travel 'of the check. valvee u pped port. I j

4. In a fluid pressureeoperated device, a rotary head structure incorporating means for mountns o a tarvsh said headstructure efi s a pres ure a be an a port thro h a wall thereof connecting the'pressure chamber to atmosphere, an inwardly-openmg check valve closing said port and having a surface exposed to tmosph re th ou a d po and a sonrotary nozzle adapted for connection to as'ource of fluid under pressure and positioned to. direct a highly concentrated jet of fluid toward the head and the path of travel of. the check valve,- equipped port, said check valve p i g under the impact of the jet when the pressure of the jet against the outer surface of the check valve exceeds the pressure against the inner surface thereof. v

5. In a fluid-operated device, a head structure, said head structure defining a pressure chamber and an elongated P011; through a wall-theme; connecting said valve chamber to atmosphere, an inwardly-opening check valve closing said port and having a surface exposed to atmosphere throu h id o t a nozzle ada t d e c n-n tion to a source of fluid under pressure DOsiion d to di ec co n a e j t o time t wa d d ead a d c e al e-compl ed port. said head and said nozzle being mounted for relative movements one with respect to the other, said check valve closing said port at all points where internal pressure exceeds atmospheric pressure and having sufiicient resilience to permit unseating at localized areas of much less extent than the length of the valve port, whereby upon relative movement of said head with respect to said nozzle said valve will be opened only at the constantly changing localized area adjacent said nozzle by the concentrated fluid jet directed by said nozzle against said valve.

6. In a fluid pressure-operated device, a rotary head structure incorporating means for mounting on a rotary shaft, said head structure defining a pressure chamber and an elongated arcuate port through a wall thereof connecting said chamber to atmosphere, an inwardly-opening check valve closing said port and having a surface exposed to atmosphere through said port, and a non-rotary nozzle adapted for connection to a source of fluid under pressure and positioned to direct a concentrated jet of fluid toward the head and the path of travel of the check valveequipped port, said check valve closing said port at all points where internal pressure exceeds atmospheric pressure and having sufficient resilience to permit unseating at localized areas of much less circumferential extent than the circumferential length of the valve port, whereby upon rotation of said head said valve will be opened only at the constantly changing localized area adjacent said nozzle by the concentrated fluid jet directed by said nozzle against said valve.

7. The structure defined in claim 6 in which said port and said valve are annular in shape and are concentric to the axis of rotation of said head.

ELWIN L. PETERSON.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 728,458 Hanson May 19, 1903 2,360,590 Schweller Oct. 17, 1944 2,370,729 Hoppe Mar. 6, 1945 2,392,999 Redmer Jan. 15, 1946 2,477,773 Sousslofi et a1 Aug. 2, 1949 2,500,383 Sadler et a1 Mar. 14, 1950 

